LEWISTON, Maine — You may not think of a Chihuahua as a “service dog,” but a review of city records show at least two of the breed along with pit bulls, pugs, Pekingese, Yorkshire terriers and a Dachshund receive free dog licenses because of the benefits they provide their disabled owners.

The number of dogs being verified by doctors and other health care professionals as either performing tasks for their owners or improving an owner’s “health and well-being” are on the rise in Maine.

Records in Bangor, Portland and Lewiston show dramatic increases in the number of dog owners seeing their $7 to $11 license fees waived.

Bangor’s service-dog population has more than doubled in three years, from 15 to 34, while Portland’s has more than quadrupled, from 10 to 43. In Lewiston, the population is up sixfold, from 4 to 25.

Of the 25 dog owners getting license waivers in Lewiston, 13 get free licenses because their dogs “improve health and well-being of the individual by mitigating a disabling condition.”

Eight dogs given waivers in Bangor fall into the same category.

The trend of more people being “prescribed” dogs may also be adding to the confusion around state and federal law that allows those with “service dogs” to take them into stores, restaurants, hotels and even on planes.

Some who use highly trained dogs that perform specific tasks, such as guiding a blind person or sensing an epileptic seizure, are frustrated that some dog owners are simply dressing their dogs as service animals to take them wherever they go. Vests, backpacks and badges are readily available online.

“You can Google up anything,” said Marie Gagnon, a service-dog trainer and kennel owner in Otisfield. She said she gets four or five calls per year from people looking for a way to get a “service animal” vest for a family pet, “‘because, you know, we are taking a trip, and we want to take Fluffy on the plane with us.'”

The first thing she tells them is that the practice is illegal in Maine and against federal law as well. She said many people don’t realize a person is responsible for damages or injuries dogs cause in public spaces, whether or not they are service dogs.

“You are liable for that and people don’t consider those things when they decide to pretend they have a service dog,” Gagnon said.

Besides the online purchase of service-animal wear, some entities sell certification papers. But the certification is essentially meaningless under the law.

“It’s not worth the paper it’s written on,” Gagnon said.

Under the Americans with Disabilities Act, it’s a federal crime to use a fake service animal. And about a fourth of all states have laws against service-animal misrepresentation. But privacy protections built into the laws make it nearly impossible to prosecute offenders.

There’s also confusion over what is and is not a service dog and what a dog owner or handler has to disclose, under the law, to a shop owner or other person who challenges a dog’s authenticity.

It’s even more difficult because no papers are legally required for real service dogs.

All a person can ask an individual with a service dog is, “Is that a service dog?” and, “What task does it do?” You can’t ask the owner to have the dog perform its task or ask what a person’s underlying disability is.

Gagnon suspects the problem of people faking service dogs is not as big in Maine as it may be in other parts of the U.S., but that may simply be because we also have fewer people than most places.

She said the family pet being registered as a service dog because it “makes you feel better when it’s with you” is not a service dog as defined under state or federal law.

The waiver application form for the dog-license fee discloses that it’s for licensing purposes only.

Because a doctor, nurse or social worker signed off on the pet doesn’t give it carte blanche to travel everywhere with you. It also doesn’t mean a dog that isn’t getting its license fee waived is not a real service dog.

The application for a waiver allows the agency that trained or owns the dog to verify it performs specific jobs for its handler.

Only two of the dogs receiving waivers in Lewiston have been verified by training organizations. One dog is listed for performing mobility assistance and 10 are listed for performing tasks for their owners. One dog —a beagle — receives a license-fee waiver but is not listed in any of the categories of service.

Eric Dibner, Maine’s coordinator for the Americans with Disabilities Act, said the rules for service dogs are complicated and often confusing, and the situation is made more confusing by the increase in the variety of breeds and types of service dogs out there.

Dibner said he didn’t know whether there were more fakers out there but said there certainly is a public perception that there may be.

Based on his understanding, Dibner said, “If it ain’t performing work, it doesn’t get to go with you into a public place.”

But a specific dog’s work is not always clear, Dibner said. He said federal and state laws have enforcement mechanisms to protect the rights of people with disabilities and to protect their access to public places, but there’s no process for challenging an “impostor” service dog.

Unlike the state’s system for handicapped-parking placards, which a police officer can track back to the rightful bearer, there’s no way to check a service dog’s credibility.

Dibner said he didn’t think people faking service dogs in Maine is a widespread problem.

“But I’m sure there are people who do that and always have,” he said. He said the license fee waiver process at least adds “some tinge of legitimacy and a document trail.”

Dibner and others said they did not know of any case in which a person had been fined for having an impostor service dog in Maine.

“I would like to see some legislation or rule developed that explains what course of action you should follow if you think someone else is an impostor,” Dibner said. He said a firm “disincentive to misrepresent” your dog would help society right itself.

The solution would be a strict licensing process for service dogs, Dibner said. Some have even advocated that service dogs and their handlers be required to carry identification, but civil rights advocates argue that could undermine the intent of the ADA.

Corey Hudson, chief executive officer of Canine Companions for Independence in San Rafael, Calif., and president of Assistance Dogs International, a coalition of training schools, is leading the effort to get the U.S. Department of Justice involved. He began writing to the agency 18 months ago but has not received a response.

Hudson wants to open talks and explore ways to identify the real from the phony.

But the International Association of Assistance Dog Partners in Michigan worries that bringing in the Justice Department could set back access rights won by those with disabilities in the past 20 years.

“While we deplore those who might be so unethical as to impersonate a disabled person by dressing their dog up as a service animal, we equally deplore the frenzy of alarm being stirred up about the risk of such abuse,” said Joan Froling, chairwoman of the association.

A standard ought to be in place, said Jennifer Arnold, founder of Canine Assistants in Atlanta. “The sticky part is who will do the testing and what will be the criteria for allowing dogs to be considered assistance dogs.”

An ID card might be the simplest answer, she said, adding that she didn’t think the loss of privacy would be the big issue some think it would be.

There is a big difference in the behavior of real service dogs and impostors inside businesses, experts said. A true service dog becomes nearly invisible. Pets might bark, urinate, sniff, scratch and eat off the floor.

Doris Dennee, a Portland-based volunteer puppy raiser for Guiding Eyes for the Blind, said only about 50 percent of puppies — even those specifically bred to be guide dogs — can actually make it through the training and meet the standards allowing them to be handled in busy public places.

“It’s an extremely high standard, and the most difficult of all the standards to meet is how the dog performs in public,” Dennee said. It’s a guide dog’s decision-making ability that sets it apart.

Dennee said she recognizes the health benefits for humans interacting with dogs and she participates in a program at Maine Medical Center in Portland that brings dogs to visit with patients.

“But those are not service dogs; those are dogs just visiting people,” she said.

She wouldn’t speculate on how prevalent fake service dogs are in Maine, but it’s a hot topic for Guiding Eyes for the Blind, which is working to improve enforcement of the federal law.

“There are people who game the system,” Dennee said. “And it’s kind of disturbing for people who legitimately have the need for a service dog.”